Structural and new spectroscopic properties of neutral [M(dmit)2](dmit = C3S2-5, 1,3-dithiole-2-thione-4,5-dithiolate) and [M(H2timdt)2](H2atimdt = H32C3M2S1-3, monoanion of imidazolidine-2,4,5-trithione) complexes within the density functional approach.

The authors give a detailed description of the structural, electronic and optical properties of the [M(dmit)2] (M = Ni, Pd, Pt) neutral dithiolenes by calcg. their geometries, their bonding energies, their vibrational spectra, their ground and exited electronic states within the d. functional approach. The dominant relativistic effects are treated by using the zeroth-order regular approxn. The authors compare their properties with those of the similar [M(H2tmidt)2] (M = Ni, Pd, Pt) series of dithiolenes and the authors find, in particular, that the LUMOs in the [M(dmit)2] compds. lay at energy very close to those of the HOMOs in the corresponding [M(H2tmidt)2] compds., which indicates the mixed-ligand complexes as possible nonlinear optical materials. The anal. of the UV-visible-NIR spectrum of the [Ni(dmit)2] complex shows that the intense NIR absorption is red shifted with respect to that in [Ni(H2tmidt)2], which may candidate this compd. as dyes for Q-switching and/or mode locking the Nd:YAG and Nd:YLF lasers. [on SciFinder(R)